Ranking - Utilities (iPhone)
Trimmer by Simplexify
App screenshots should be submitted without the status bar, and Trimmer gives an easy way to produce these images. Screenshots without the status bar are also more appropriate for publications.
Photos are saved at the same resolution as the original screenshots (minus a bit at the top where the status bar was).
Note that Trimmer does not take the photos, this functionality is built into your device. Just press the home button and the top "off" button simultaneously, and a screenshot will be saved to your photo library.